1. The Field of the Invention
This application relates generally to drilling methods and devices used in drilling. In particular, this application relates to pneumatic drifters containing a drifter cylinder with removable feet and associated methods for using the pneumatic drifters.
2. The Relevant Technology
Many drilling processes are currently known and used. One type of drilling process, rock drilling, often includes drilling holes in a rock or other hard formation to fracture the rock so it can be removed. If necessary, explosives can also be placed in the holes and used to break and fracture the rock further. One type of drill used in rock drilling is commonly known as a “drifter.”
Drifters are usually powered by pneumatic or hydraulic pressure. Because of maintenance considerations, pneumatic drifters are used more commonly than hydraulic drifters. Pneumatic drifters include a cylindrical drilling mechanism (also called a drifter cylinder) that is mounted in a sliding frame and driven in the direction of the hole being drilled by an air driven feed mechanism, such as a screw or chain. The drifter uses percussion, rotation, and pressure to drill the desired hole in the hard formation.
The sliding frame of the drifter, also called a feed slide, may be made of aluminum to save weight and enhance portability. The body cylinder is coupled to the feed slide by using integral two foot pieces. The drifter cylinder, including the integral foot pieces, is a precision-manufactured component that can be both large and costly. During operation, the foot pieces of the cylinder can wear rapidly due to the grit resulting from the drilling process. Although the slide frame is usually made of a softer material than the drifter cylinder, the drifter cylinder foot pieces wear more quickly than the slide frame because the grit embeds in the softer material of the slide frame, wearing on the drifter cylinder foot pieces as the drifter cylinder slides along the slide frame. This wear results in failure of the drifter cylinder feet, requiring replacement or expensive repair of the entire drifter cylinder.